powerpc/smp: Do not disable IPI interrupts during suspend

During suspend, all interrupts including IPI will be disabled. In this case,
the suspend process will hang in SMP. To prevent this, pass the flag
IRQF_NO_SUSPEND when requesting IPI irq.

Signed-off-by: Zhao Chenhui <chenhui.zhao@freescale.com>
Signed-off-by: Li Yang <leoli@freescale.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>